Diffuser drape

ABSTRACT

The invention relates to diffuser drapes and has a particularly useful application in such drapes as those used in surgical operations. Early experiments met with difficulties in providing a diffuser drape which would produce the necessary air patterns to keep the work surface clean and would not interfere with the regular activities of the operator. The diffuser drape comprises an apertured drape member with an inflatable clean air duct integral with the drape and surrounding the aperture. The clean air duct has a diffuser in it which surrounds the aperture and is shaped to diffuse low velocity clean air radially therethrough outwardly of the periphery and inwardly across the aperture from opposites sides thereof to produce a resultant flow away from the aperture. Two clean air inlets for the duct are provided on the underside of the drape member. The duct is preferably eliptical in shape and the inlets are sleeves which flare to merge tangentially into the duct.

United States Patent Criddle et a1.

DIFFUSER DRAPE Inventors: Ernest E. Criddle; Pierrette L. Neals, both of Ottawa, Canada Assignee: Canadian Patents and Development Limited, Ottawa, Canada Filed: Mays'll, 1974 Appl. No.: 471,886

[30] Foreign Application Priority Data May 16, 1974 Canada 200154 References Cited UNITED STATES PATENTS 12/19'42 Coburg 123/132 R 10/1971 Rich 128/132 D 9/1972 Von Otto., 128/132 R 10/1973 Schrading 128/132 D Dec. 23, 1975 3,824,987 7/1974 Howorth 128/1 R Primary ExaminerRichard A. Gaudet Assistant Examiner-Henry J. Recla ABSIRACT The invention relates to diffuser drapes and has a particularly useful application in such drapes as those used in surgical operations. Early experiments met with difficulties in providing a diffuser drape which would produce the necessary air patterns to keep the work surface clean and would not interfere with the regular activities of the operator. The diffuser drape comprises an apertured drape member with an inflatable clean air duct integral with the drape and surrounding the aperture. The clean air duct has a diffuser in it which surrounds the aperture and is shaped to diffuse low velocity clean air radially therethrough outwardly of the periphery and inwardly across the aperture from opposites sides thereof to produce a resultant flow away from the aperture. Two clean air inlets for the duct are provided on the underside of the drape member. The duct is preferably eliptical in shape and the inlets are sleeyes which flare to merge tangentially into the duct.

3 Claims, 2 Drawing Figures US. Patent Dec. 23, 1975 Sheet 1of2 3,927,667

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DIFFUSER DRAPE BACKGROUND. OF THE INVENTION The present invention relates to a diffuser drape for providing a clean work area, such as, for example, the wound site of a surgical operation.-

It has been proposed in the past to provide a clean area by positioning clean air diffusers to diffuse clean air over a work surface and it has further been proposed to provide a clean air difluser in a surgical drape.

The previous experimental attempts to provide a practical diffuser-drape,- however, met with difficulties in integrating the diffuser into a drape in. a fashion which provided the necessary clean air pattern without at the same time getting in the operators way. Furthermore, with earlier proposals, the difl'used air pattern frequently broke down because of regular activities by the operator.

SUMMARY OF THE INVENTION According to the present invention a diffuser drape comprises a drape member having an aperture therein;

inflatable clean air duct means attached to said drape and surrounding said aperture; said clean air duct means having difluser means therein surrounding said aperture and shaped to diffuse, in operation, low velocity clean air radially through said difluser means inwardly across said aperture from opposite sides thereof to produce a resultant flow away therefrom; and at least two clean air inlets for said clean air duct means on the underside of said drape member. According to a preferred feature of the invention the flow of clean air from the duct means is also outwardly of the periphery of the difl'user.

Another problem encountered with earlier experimental diffusers was how to avoid the jetting of air at the point where an inlet hose, or the like, encountered the difluser and, according to a preferred feature of the invention, the clean air inlets comprise sleeve means which are widened as they approach the duct means and merge therewith.

Yet a further problem encountered with earlier proposals was to provide even distribution of air and, preferably, the clean air duct means is formed in a substantially elliptical shape. Preferably also the clean air inlet sleeve means are flared to merge substantially tangentially into the duct means.

According to a further feature of the invention the clean air inlets, which comprises sleeve means, are obliquely inclined to the longitudinal or transverse axis of the aperture and, in diffuser drapes used for abdominal surgery and the like, the sleeve means are preferably inclined at an angle of between 22 and 35 to the longitudinal axis of the aperture and preferably at an angle of 27 thereto.

BRIEF DESCRIPTION OF DRAMNGS The following is a description by way of example of one embodiment of the present invention, reference being had to the accompanying drawings in which:

FIG. 1 is a diagramtic underside plan view of a diffuser drape showing the diffuser means attached to the drape; and

FIG. 2 is a cross-section of the line [I ll of FIG. 1, looking in the direction of the arrows.

DESCRIPTION OF PREFERRED EMBODIMENT Referring now to the drawings, drape 10, which may be a surgical drape, is provided with an aperture 11 therein. The aperture 11 may be of square or round shape but as shown, is elliptical.

An inflatable clean air duct means 12 is sewn into the drape so as to become integral therewith and surrounds the aperture. The clean air duct is itself of substantially elliptical shape. The duct has a diffuser 13 therein (shown in dotted outline in FIG. 2) and the diffuser is shaped so that, in operation, it will provide a current of clean air radially inwardly across the aperture as indicated by the arrows 14 in FIG. 2. In the preferred configuration, a current of clean air is also provided outwardly of the periphery of the diffuser, as indicated by the arrows 15 in FIG. 2. The air pattern from the diffuser across the work space 16, from opposite sides thereof, which is the case of a surgical drape would be a patient s body, results, in known fashion, in an outwardly flow 18 of air away from the work surface 16.

The diffuser duct portion is made of a similar material to the material of the drape 10 whilst the diffuser 12b (dotted in FIG. 2) may suitably be of a different material. The material of the duct portions 12a may be cotton of to threads per inch and the diffuser means 12b may be of a plain weave cotton material weighing 5.2 oz/yd sold under the Dominion Textiles trade name TOWN AND COUNTRY and having 50 threads per inch in the warp and 43 threads per inch in the weft.

With this configuration, and particularly when the duct portion 12a is of cotton about 140 threads per inch, a very slight diffusion (almost in the form of a leakage) takes place radi ly through the duct portion 120 as indicated by the news 130. This minor diffusion can have beneficial effects in some applications. If unwanted, this minor diffusion may be reduced by doubling the number of layers of material or by making the material less permeable.

So that the air pattern will not break down in the event of the operation (perhaps a surgeon) leaning on the diffuser duct during operation, at least two inlets, or mouths 20, are provided integrally with, and of the same material as, the duct portion 120. The inlets comprise a widened sleeve portion merging with the diffuser duct, and in the elliptical configuration shown the widened sleeve means merge tangentially at 21 with the difluser duct. The inlets continue outwardly at 22 from the aperture, on the underside of the drape. If the surgeon, or operator, collapses the diffuser means 13 by placing a hand or instrument on it at one point, air will still be provided to the diffuser as a whole because of the second inlet. For some types of function it may be necessary to supply a third, or even a fourth, inlet.

Air is normally supplied by means of hoses from a clean air source which hoses are inserted into the upstream extensions 25 of the sleeves where the sleeves are tied by means of ties 26 around the hoses. The clean air source, which is positioned remotely from the drape, is of a type known per se. It delivers clean air through the diffuser such that the air flow from the v ork space 16 is at about I00 ft/min (fpm). The velocities often used in the clean air art are 90 fpm plus or minor 20 fpm. In small diffusers such as shown, the range may be 90 fpm plus or minus 40 fpm. With an elliptical diffuser drape as seen in FIGS. l and 2 having 3 a work space 16 of about 2 sq. ft., the volume of clean air supplied would be about 200 cfm.

The widening of the inlet to provide a smooth merging with the ducting is an important preferred feature of the invention because it provides for the smooth diffusion of air into the duct means. Furthermore, the substantially elliptical shape of the diffuser and the duct means is also an important preferred feature because unlike a rectangular configuration it provides for a smooth and even flow of air'and an even distribution of air through the diffuser.

As shown in FIG. 1 the drape is a surgical drape for abdominal surgery the sleeve means 22 are inclined at the oblique angle to the longitudinal axis 28 and the traverse axis 29 of the aperture 11. This also is an important preferred feature of the invention for this type of use because it provides a configuration in which the clean air can be delivered to the aperture 11 without the hoses getting in the way of the operator.

It has been found that for abdominal surgery the angle a of the center line of the sleeve from the longitudinal axis should be between 22 and 35 and with the optimum angle being 27.

What we claim as our invention is:

l. A diffuser drape comprising:

a. a drape member having a substantially elliptical aperature therein;

b. inflatable clean air duct means of substantially elliptical shape integral with said drape and surrounding said aperture;

c. diffuser means in said clean air duct means surrounding said aperture and shaped to difluse, in operation, low velocity clean air radially through the diffuser means outwardly of the periphery thereof and inwardly across said aperture from opposite sides thereof to produce a resultant flow away therefrom; and

d. at least two opposed clean air inlets for said clean air duct means on the underside of said drape member, which clean air inlets are sleeve means flared to merge substantially tangentially into said duct means and inclined at an angle of between 22 and 35 to the longitudinal axis of said aperture.

2. A diffuser drape as claimed in claim 1 in which the air duct means is of a material which; in operation, difl'uses a small amount of clean air radially therethrough in addition to die air through the diffuser means.

3. A diffuser drape as claimed in claim 1 in which said sleeve means are inclined at an angle of 27 to the longitudinal axis of said aperture.

=0 I II! t 

1. A diffuser drape comprising: a. a drape member having a substantially elliptical aperature therein; b. inflatable clean air duct means of substantially elliptical shape integral with said drape and surrounding said aperture; c. diffuser means in said clean air duct means surrounding said aperture and shaped to diffuse, in operation, low velocity clean air radially through the diffuser means outwardly of the periphery thereof and inwardly across said aperture from opposite sides thereof to produce a resultant flow away therefrom; and d. at least two opposed clean air inlets for said clean air duct means on the underside of said drape member, which clean air inlets are sleeve means flared to merge substantially tangentially into said duct means and inclined at an angle of between 22* and 35* to the longitudinal axis of said aperture.
 2. A diffuser drape as claimed in claim 1 in which the air duct means is of a material which; in operation, diffuses a small amount of clean air radially therethrough in addition to the air through the diffuser means.
 3. A diffuser drape as claimed in claim 1 in which said sleeve means are inclined at an angle of 27* to the longitudinal axis of said aperture. 